JP2013507738A - Actinic or electron beam curable electrode binder and electrode comprising the same - Google Patents

Abstract

A method of manufacturing an electrode is provided that includes curing an electrode binder polymer by electron beam (EB) or actinic radiation. A step of mixing actinic radiation or electron beam curable chemical precursor with electrode solid particles to prepare a mixture; a step of applying the mixture onto an electrode current collector; Exposing the mixture to actinic or electron beam to cure, thereby bonding the electrode solid material to a current collector. Also provided are lithium ion batteries, electric double layer capacitors, and the components that make them.
[Selection] Figure 1

Description

  The present invention relates to the technical field of electrodes that can be used in alkaline ion secondary (rechargeable) batteries, and more particularly to the technical field of lithium ion secondary batteries, electric double layer capacitors, and methods of manufacturing the same.

  It is known that an electrochemical device such as a battery or an electric double layer capacitor (EDLC) is very excellent for use in a power source of a portable device or an auxiliary power source of an automobile. For example, lithium ion batteries are one of the most popular types of batteries used in portable electronic devices such as cell phones, portable music players, and portable computers. Lithium ion batteries have a very high energy-to-weight ratio, do not produce a memory effect, and discharge the charging electricity when not in use. Lithium ion batteries are also gaining popularity in military, electric and aerospace applications due to their high energy density.

  The basic operating unit of a lithium ion battery is an electrochemical cell. The electrochemical cell includes a pair of electrodes (anode and cathode) that are spaced apart and connected to each other by an electrolyte. The anode is typically a thin metal sheet of conductive material such as copper (called an anode current collector), which is coated with solid anode material particles. The solid particles are generally bound to the anode current collector by a binder, which is a polymer that generally retains binding and hardness and does not swell or decompose during use, or The particles are bonded together. Common anode particles include carbon (typically graphite) or silicon-based materials. The particle size of the anode material coated on the current collector ranges from a few nanometers to a few microns in nominal diameter.

The electrolyte of a lithium ion battery can be a liquid, a solid or a gel. In the case of a liquid electrolyte, a separator is used to separate the anode from the cathode. A common separator is a thin porous polymer sheet. The polymer voids are filled with an electrolyte. A common liquid electrolyte is a mixture of organic carbonates, such as alkyl carbonates containing lithium ion complexes. The lithium ion complex is generally a non-coordinating anion salt, such as lithium hexafluorophosphate (LiPF ₆ ), lithium hexahexafluorolithium arsenate monohydrate (LiAsF ₆ ), Examples include lithium perchlorate (LiClO ₄ ), lithium tetrafluoroborate (LiBF ₄ ), and lithium triflate (LiCF ₃ SO ₃ ). A common solid electrolyte is a polymer. Various materials can be used as the gel electrolyte. The electrolyte is designed to withstand the voltage between the anode and cathode and can provide high mobility of lithium ions without the risk of flammability.

  Cathodes commonly used in lithium ion batteries include a thin metal sheet (referred to as a cathode current collector) of a conductive material, such as aluminum, and are coated with solid cathode particles. The cathode solid particles are bound to the cathode current collector by a solid polypeptide binder or the particles are bound to each other. The solid polypeptide binder is generally a polymer made to retain binding and hardness and not swell or degrade during use. Common cathode materials include particles of metal oxides such as oxides of lithium, cobalt, magnesium, nickel or vanadium, and other lithium compounds (eg, lithium iron phosphate). The cathode material often contains a small amount of carbon (although not as graphitic as the carbon contained in the anode) to improve conductivity. The particle size of the cathode material coated on the current collector ranges from a few nanometers to a few microns in nominal diameter.

  EDLC, also called supercapacitor or ultracapacitor, is an electrochemical capacitor that has a very high energy density compared to conventional capacitors. An EDLC includes two electrodes of the same structure separated by an intervening material. The separation mediator provides effective charge separation despite separating the two electrode layers by a very small physical distance (in nanometers). As the electrode of the EDLC, a current collector (for example, aluminum) similar to the current collector of the cathode of a lithium ion battery is generally used. To increase the energy storage density, a porous material, typically granular carbon such as graphite or activated carbon, is applied to the surface of the current collector by a binder. The binder is generally a polymer made to retain its bondability and hardness and not swell or decompose during use. Carbon particle size generally ranges from a few nanometers to a few microns in nominal diameter. Thereafter, the pores of the electrode carbon are filled with an intervening substance, that is, a liquid or gel electrolyte. A common liquid electrolyte is an organic alkyl carbonate that can include a selected lithium salt.

The general production method of the electrode used for a lithium ion battery or EDLC is as follows.
(1) A polymer binder is dissolved in a solvent, and a solution having a viscosity suitable for application to a current collector after mixing with electrode solid particles is prepared.
(2) The low-viscosity binder solution is mixed with the electrode solid particles in a solvent of about 20 to 80% by weight, particularly about 50% by weight, to form a paste.
(3) The paste is coated on the current collector using a conventional coating technique to form a thin layer (generally 10 to 200 microns).
(4) The coated current collector is put in a heat drying oven to evaporate and remove the solvent and cure the binder polymer.
(5) The electrode current collector thus produced is passed between a pair of rotating rollers separated from each other by a narrow gap (for example, 5 to 200 microns), and the current collector coating is compressed to a predetermined thickness. To do.
(6) In general, both sides of the electrode current collector are coated with anode / cathode particles and treated in the steps described above.

The above-described prior art relating to the manufacture of electrodes has several problems that directly affect manufacturing costs. Such problems include, but are not limited to:
(A) A large heat energy input is required because the solvent used to dissolve the polymer binder must be evaporated.
(B) The energy efficiency associated with heat drying is very poor.
(C) The evaporated solvent needs to be recovered and discarded or reused.
(D) A large capital cost is required because the oven required to dry the polymer binder occupies a large work space.
(E) Since it takes time to dry the polymer binder in the drying oven, the time required for manufacturing the electrode becomes longer.

  Accordingly, there is a need in the art for improved materials and methods for making electrodes. For example, improved binders used in cathodes and anodes of lithium ion batteries and EDLC electrodes would be very useful.

U.S. Pat.No. 4,218,349 U.S. Pat.No. 5,300,569

  According to one embodiment, the present invention provides an electrode comprising a current collector (current collector) and a cross-linked polymer layer bonded to the current collector. The polymer layer includes a cross-linked matrix formed from a rubber polymer. Examples of the rubber polymer include monomer units of isoprene, butadiene, cyclopentadiene, ethylidene norbornene, or vinyl norbornene, or combinations thereof. Advantageously, the cross-linked matrix can be formed by actinic or electron beam curing. For this purpose, the crosslinked matrix includes an actinic / electron beam reaction curable crosslinking agent covalently bonded to the crosslinked rubber polymer.

  The cross-linked polymer layer further includes a particulate material. The particulate material may be carbon such as graphene, activated carbon, graphite, low sulfur graphite, carbon nanotubes, or combinations thereof. The cross-linked polymer layer may include a particulate material such as a metal oxide salt or a lithium compound.

  Optionally, additional layers such as a second electrode, separator, electrolyte layer, etc. can be provided adjacent to the electrode of the present invention. For example, in a battery (eg, a lithium ion battery) or an electric double layer capacitor (EDLC), another electrode can be disposed adjacent to the electrode of the present invention.

  The present invention also provides a method for manufacturing an electrode. For example, the method of the present invention includes the step of mixing the binder coating composition with the electrode particulate material to prepare a mixture. The binder coating composition includes a functionalized rubber polymer. In addition, the binder coating composition includes a cross-linking agent that can form a covalent bond when exposed to actinic or electron beams. The binder coating composition has a melt viscosity of less than about 20 Pascal seconds so that a coating layer can be formed.

  The method of the present invention also includes applying the mixture to a surface of a current collector to form a mixture layer, and exposing the mixture layer to actinic or electron beams, thereby cross-linking the functionalized rubber polymer. Further comprising the step of:

  The binder coating composition may further comprise additional materials such as reactive diluents, wetting agents or photoinitiators. In one embodiment, the cross-linking agent also serves as a diluent.

It is a top view of one embodiment of an electrode manufacturing process indicated in this specification. It is a top view of another embodiment of an electrode manufacturing process indicated by this specification. 1 is a cross-sectional view of a lithium ion electrochemical cell according to an embodiment of the present invention. 1 is a cross-sectional view of an EDLC according to an embodiment of the present invention. 2 is an electrochemical cell initial charge and discharge curve made in accordance with the present invention. 2 is an electrochemical cell initial charge and discharge curve made in accordance with the present invention. 2 is an electrochemical cell initial charge and discharge curve made in accordance with the present invention.

  Various embodiments of the invention are described in detail below, and one or more examples are given below. Each example is provided by way of explanation and not as a limitation of the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the scope or spirit of the invention. For example, still other embodiments can be generated by applying features described or illustrated as part of one embodiment to another embodiment. Accordingly, the present invention is intended to encompass such modifications and variations.

  In general, the present invention relates to a method of manufacturing an electrode that does not require the costly oven drying or solvent treatment described above, and products such as lithium ion batteries and EDLCs incorporating the electrode. More specifically, the electrode of the present invention contains a polymer binder that can be cured by actinic radiation or electron beam (EB). The term actinic radiation as used herein is intended to refer to electromagnetic radiation that can produce a photochemical effect. For example, the polymer binders of the present invention can be cured by actinic radiation in the ultraviolet (UV) spectrum or visible spectrum. The present invention applies a mixture prepared by mixing a chemical precursor that can be cured by actinic radiation or EB with solid particles to a current collector of an electrode, and then covalently crosslinks the polymer. Exposing the mixture-coated current collector to a suitable light beam for curing, thereby bonding the particles to each other or to the cross-linked polymer matrix, and to attach the electrode material to the current collector. Provide a method of bonding.

  Until now, conventional UV / EB curable binder resins have not been successfully used in the manufacture of electrodes. In general, the reason is believed to be due to the harsh conditions that exist in the operating state of the electrode (eg, heating or corrosiveness of lithium ion batteries). The majority of conventional binder resins have poor bondability to metals and, for example, chemical resistance to electrode materials.

  The present invention provides a functionalized polymer that can be cured by EB and / or actinic radiation and used as a binder in the manufacture of electrodes. The polymeric material of the present invention exhibits good binding to current collectors (eg, copper or aluminum) and the required resistance to harsh operating conditions and electrode materials that exist in both batteries and EDLCs I will provide a.

  In one embodiment, the functionalized polymer is made based on a rubber polymer. Exemplary rubbers suitable for use in the present invention include functionalized polyisoprene and / or polybutadiene rubbers. U.S. Pat. No. 4,218,349, which is incorporated herein by reference, describes a polyisoprene rubber composition that can be suitable for use in the present invention and a method of making the same. In addition, US Pat. No. 5,300,569 (Patent Document 2), which is incorporated herein by reference, describes a polybutadiene rubber composition that can be used in the present invention and a method for producing the same. The binder of the present invention is not limited to a rubber composition containing only isoprene and / or butadiene polymer. Functionalized rubber oligomers or polymers that can be used to make the binders of the invention can include at least one of isoprene, butadiene, cyclopentadiene, ethylidene norbornene or vinyl norbornene monomer units, or combinations thereof. .

  The rubber polymer or oligomer is functionalized to include reactive groups that improve the bondability to the metal and / or curability via EB / Actinic radiation crosslinking. For example, carboxy, acrylic, vinyl, vinyl ether or epoxy functionalized polyisoprene and / or polybutylene rubbers that cure upon exposure to electron or actinic radiation (ultraviolet rays) can be used. Exemplary functionalized polymers include, for example, Isolene® resin commercially available from Elementis, Heightstown, NJ, and commercially available from Chemtura, Middlebury, Connecticut. Trilene® resin, liquid isoprene rubber (LIR) commercially available from Kuraray Co., Pasadena, Texas, Kraysol (Sartomer Co., commercially available from Sartomer Co., Exton, Pa.) Commercially available from liquid butadiene rubber (LBR), such as registered trademark), Ricon®, Riacryl® and Polybd® resin, or San Esters, New York, NY There is BAC resin.

  In one embodiment, the binding agent of the present invention has an isoprene backbone having one or more reactive functional groups attached thereto. Such binders have been found to give excellent results as polymer binders in forming electrodes such as cathode or anode electrodes useful for lithium ion batteries, for example. In one embodiment, suitable binders include a carboxylated methacrylated isoprene backbone, represented by the chemical formula:

  Where m is about 10 to about 1000, or about 100 to about 1000, or about 200 to about 500, and n is 1 to about 20, or 1 to about 10, or about 2 to about 10, or about 2 to about 5.

  Another embodiment of a suitable binder includes a carboxylated methacrylated butadiene backbone represented by the chemical formula:

  Where m is about 10 to about 1000, or about 100 to about 1000, or about 200 to about 500, and n is 1 to about 20, or about 1 to about 10, or about 2 to about 10, or From about 2 to about 5.

  Another embodiment of a suitable binder includes a butadiene backbone represented by the following chemical formula:

  However, n is about 5 to about 2000, or about 10 to about 1500, or about 100 to about 1000.

  Of course, the binder of the present invention can include a plurality of different backbone portions. An example is an isoprene-butadiene copolymer. The binding agents of the present invention are generally from about 7,000 to about 110,000, or from about 10,000 to about 100,000, or from about 10,000 to about 50,000, or from about 15,000 to about 40. May have a molecular weight of 1,000.

  The rubber binder polymer is present in the binder coating composition from about 20% to about 100%, or from about 25% to about 75%, or from about 30% to about 70%, or It may be included in an amount of about 40% to about 60% by weight.

  Suitable functionalized isoprene-based or butadiene-based rubbers include, but are not limited to, products UC-102, UC-105 and UC-203, available from Kuraray, Pasadena, Texas, and Exton, PA. Included are oligomers commercially available under the trade names CN301, CN303 and CN307 from Sartomer, Inc.

  The actinic radiation / EB curable polymer binder disclosed herein has a melt viscosity (at 38 ° C.) of less than about 2000 Pa · s, such as about 5 to about 500 Pa · s, or about 20 to about 200 Pa · s. Have. When making an electrode using the binder of the present invention, a reactive diluent is added to reduce the melt viscosity to facilitate coating. Reactive dilution to reduce the melt viscosity of the binder coating composition to less than about 10 Pa · s, such as about 5 Pa · s, or about 1.5 Pa · s, or about 1 Pa · s, depending on the properties of the polymer The agent is added. As used herein, the term binder coating composition is intended to refer to a pre-cured composition that is applied to the current collector, and a specific that is applied to the current collector with the binder coating composition. This substance is not included. For example, the term binder coating composition refers to a composition before being premixed with lithium metal oxide particles or graphite particulates and before curing.

  Although it is desirable to use a polymer having a melt viscosity of about 2000 Pa · s or greater, a large amount of diluent is required to reduce the melt viscosity of such binder coating compositions to a suitable coating viscosity. If the amount of diluent significantly exceeds the amount of polymer, not only will processing be difficult, it will be difficult to obtain the desired properties of the crosslinked polymer binder. Generally, the reactive diluent is about 90% by weight or less of the binder coating composition, such as about 10% to about 90%, or about 25% to about 75%, or about 40% by weight. To about 60% by weight. The diluent is selected so as not to reduce the binding property to the current collector and the chemical resistance of the binder. In addition, a diluent is used that is compatible with the polymer binder and has the property that it does not substantially separate from the polymer binder during mixing or application of the binder coating composition.

  The reactive diluent reacts with the functionalized rubber polymer during curing to crosslink the matrix. Accordingly, reactive diluents are also referred to as crosslinkers throughout this specification. Examples of reactive diluents encompassed herein include, but are not limited to, isobornyl acrylate, polyethylene glycol diacrylate, hexanediol diacrylate, alkoxylated hexane diacrylate, and functionalized rubber during curing. Other compounds such as acrylic acid are included that can react with the reactants to reduce the melt viscosity of the binder coating composition.

  The binder coating composition may include one or more crosslinkers that do not necessarily serve as a diluent. For example, a polymer having a suitably low melt viscosity can be crosslinked by using a crosslinking agent that does not serve as a diluent. Further, the polymeric binder coating composition can include a combination of crosslinkers, such as a combination of a crosslinker that serves as a reactive diluent and a crosslinker that does not serve as a diluent, or 2 or It can include a combination of two or more different reactive diluent crosslinkers, or two or more different combinations of crosslinkers that do not act as diluents.

  Exemplary reactive crosslinkers of the binder coating composition include those that react when exposed to EB and / or actinic radiation. Light rays suitable for each cross-linking agent are known in the art. For example, a crosslinking agent can be used that reacts when exposed to actinic radiation in the UV or visible spectrum. Examples of cross-linking agents include, but are not limited to, monofunctional acrylates, difunctional acrylates, polyfunctional acrylates, and other vinyl compounds. Suitable acrylates can be linear, branched, cyclic or aromatic. Linear acrylates can include alkyl acrylates containing 4 to 20 carbon atoms. Branched acrylates can include branched alkyl acrylates containing from 4 to 20 carbon atoms, such as, for example, ethylhexyl 2-acrylate or isostearyl acrylate. Cyclic acrylates can include dicyclopentanyl acrylate or n-vinylcaprolactam. The aromatic acrylate can include phenoxyethyl acrylate. The bifunctional acrylate or polyfunctional acrylate may include 1,6-hexanediol (meth) acrylate, 1,9-hexanediol (meth) acrylate, and tricyclodecane dimethanol diacrylate.

  The polymer binder can be cross-linked with a photoinitiator. For example, the photoinitiator can be a component of a diluent composition. The photoinitiator is present in the binder coating composition up to about 20% by weight of the composition, such as from about 1% to about 15%, or from about 1% to about 10%, or about 1%. % To about 7% by weight.

  Exemplary photoinitiators include benzophenone, hydroxyacetophenone, methylbenzophenone, 4-phenylbenzophenone, 4,4′-bis (diethylamino) benzophenone, Michler's ketone, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy- 2-Methylpropyl) ketone and other benzophenone derivatives, benzyldimethyl ketal, 2-benzyl-2-N, N-dimethylamino-1- (4-morpholinophenyl) -1butanone, 2-mercaptobenzoxazole, camphorquinone 2-hydroxy-2-methyl-1- (4-t-butyl) phenylpropane-1-non, 2-methyl-1- [4- (methylthiophenyl)]-2-morpholinopropanone, maleimide, 2, 4,5-trimethylbenzoyl-diphenyl Sphine oxide, bis (2,6-dimethyloxybenzoyl) -2,4,4-trimethylphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, polymer photoinitiation derived from the above materials Agents, and combinations thereof. In one embodiment, a propanone photoinitiator is used, such as Esacure® KIP 150 or KIP 100F from Lamberti USA, Inc., Conshohocken, PA. About 70% by weight oligo (2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone and about 30% by weight 2-hydroxy-2-methyl, sold under the trade name There is a mixture with -1-phenylpropane-1-one, which also uses other photoinitiators such as Esacure SM 303 sold by Lamberti USA under the trademark KIP or Esacure® Other polymeric photoinitiators include PL-816A from Palermo Lundahl Industries In another embodiment, the oxide photoinitiator. One suitable oxide photoinitiator is a bis (2,4,4) commercially available from Ciba Specialty Chemicals under the trade name Irgacure® 819. 6-trimethylbenzoyl) -phenylphosphine oxide Other photoinitiators sold by Ciba Specialty Chemicals under the trade name Irgacure® may also be suitable for use in the present invention.

  The binder coating composition of the present invention can optionally include other processing agents suitable for the desired coating properties. The treating agent may be included in the binder coating composition in an amount of no more than about 10%, in one embodiment no more than about 5%, or in one embodiment no more than about 2% by weight of the composition. Treatment agents suitable for use in the binder coating composition of the present invention can include, but are not limited to, binders or bond promoters. A suitable binder is γ-glycidoxypropyltrimethoxysilane, such as Silquest® A-187, commercially available from Momentive Performance Materials, Albany, NY.

  In one embodiment, a wetting agent can be included in the binder coating composition of the present invention. The wetting agent can improve the contact or wetting between the binder coating composition, the particles mixed with the binder coating composition, and the current collector substrate. Thus, the inclusion of a wetting agent in the binder coating composition can improve the bondability between the various components after curing of the binder of the present invention.

  The wetting agent can be a sacrificial material that evaporates before or during curing of the binder coating composition, or a material that remains in the product after curing. For example, the wetting agent can function as an electrode after the binder of the present invention is cured. Exemplary wetting agents include, but are not limited to, acetone, isopropyl alcohol, dimethyl carbonate, and the like. In general, any solvent or electrode material that can improve the wettability or contact between the binder coating composition, the particles and the current collector can be used. In one embodiment, wetting agents that have a low boiling point and evaporate quickly are preferred. For example, the wetting agent may have a boiling point of about 71 ° C. (160 ° F.) or less. Advantageously, the use of a low-boiling humectant allows the humectant to evaporate and dissipate during UV / EB curing, thus providing a substantial amount for solvent removal required in previously known methods. No need to input heat energy. Alternatively, wetting agents designed to remain in the material after curing and can be used as, for example, electrodes can be used.

  Referring to FIGS. 1, 2 and 3, there is shown an embodiment in which an electrode particulate material 10 (FIG. 3) and a polymer binder coating composition 9 (FIG. 3) are applied to the electrode current collector 2 as an electrode layer 5. . In FIG. 3, the electrode particulate material 10 and the polymer binder coating composition 9 are shown as separate layers, but in general, the mixture of the electrode particulate material 10 and the binder coating composition 9 is a current collector 2. The single electrode layer 5 is formed. Thereafter, the polymer of the electrode layer 5 is cured on the current collector 2 using actinic / electron beams. After forming a matrix bonded to the current collector by crosslinking, the binder not only exhibits very good binding properties to the current collector, but also exhibits excellent chemical resistance and at high temperatures. Is insoluble in the electrolyte.

  The particulate material 10 included in the electrode includes any particulate material known in the art, such as, but not limited to, graphene, activated carbon, graphite, low sulfur graphite, There are carbon particulate materials such as carbon nanotubes and silicon-based materials, and metal oxide salts such as oxides of lithium, cobalt, magnesium, nickel, or vanadium. For example, the particulate material includes a lithium compound, such as lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium nickel. There are lithium compounds such as manganese cobalt (NMC), or mixtures thereof.

  More specifically, with reference to FIGS. 1, 2, and 3, the electrode current collector supply roll 1 supplies the electrode current collector 2. The applicator 3 mixes the electrode particulate material 10 with the polymer binder coating composition and applies a thin layer 5 of the mixture onto the traveling current collector 2. Of course, the various components of the electrode particulate material 10 and the binder coating composition 9 can be premixed prior to filling the applicator 3. For example, first, the carbon particulate material and the solid binder polymer are pulverized by, for example, a 3-roll mill. Then, after mixing the carbon and binder polymer to make a solid powder mixture, the lithium compound and appropriate diluent (and any additional components such as additional crosslinkers and photoinitiators) are added to the mixture. Can be used to reduce the melt viscosity of the mixture to form a paste having an appropriate viscosity that can be applied.

  The applicator 3 applies the mixture to the current collector 2 as the electrode layer 5. This coating can be achieved by conventional coating techniques such as gravure printing, flexographic printing, slot die, reversing roll, roll knife, offset and the like.

  After the electrode layer 5 is formed, the electrode layer 5 is exposed to actinic / electron beams to crosslink the functionalized rubber polymer of the electrode layer 5. For example, when the binder coating composition is exposed to UV, visible light or electron beam, optionally in the presence of a photoinitiator, the crosslinking agent in the composition reacts with the reactive functional groups of the rubber polymer. Thus, a covalent bond is formed over the entire electrode layer. As a result, the particulate matter can be tightly enclosed in the cross-linked network, and the electrode material layer 5 can be firmly bonded to the current collector 2.

  After the electrode layer 5 is applied to the electrode current collector 2, they are passed under the actinic radiation curing device 4 and the electron beam curing device 6 in a relatively short time to cross-link each other, thereby improving the production rate and Cost can be reduced. A plurality of electrode coating material layers can also be formed using a plurality of application stations 3. Also, optionally, a separator layer is provided between the plurality of electrode coating material layers to achieve the required final thickness at high speeds (eg, about 20 feet / minute to about 400 feet / minute). You can also.

  The separator that can be disposed between the plurality of electrode coating material layers can be any separator known in the art. For example, when making EDLC or lithium ion batteries, separators made from polymer sheets such as polytetrafluoroethylene (PTFE), polypropylene (PP), polyethylene (PE), or a fused layer of PP and PE are adjacent to each other. Between a plurality of electrode layers.

  The binder coating composition 9 is generally in the electrode layer 5 from about 1% to about 20%, such as from about 2% to about 12%, or from about 2% to about 6%, Alternatively, it may be contained in an amount of about 3% to about 5% by weight. The coating mixture is generally applied to the electrode current collector 2 as a very thin layer 5. The thickness of the electrode layer 5 can be about 1 to about 500 microns, or about 5 to about 250 microns, or about 5 to about 200 microns, or about 5 to about 150 microns. The electrode layer 5 can be applied to one or both sides of the current collector 2. 1 and 2 show a system in which an electrode layer 5 is applied on both sides of a current collector 2.

  1 and 2 show a system that uses both an actinic radiation irradiator 4 and an electron beam irradiator 8. Depending on the properties of the binder coating composition, actinic radiation irradiator 4, electron beam irradiator 8, or both are used.

Referring to FIG. 1, electrolyte 6 is integrated with electrode current collector 2 and electrode layer 5. As is known in the art, the electrolyte 6 can be a solid, liquid or gel. For example, the electrolytic solution 6 may be an organic electrolyte such as carbonate (for example, ethylene carbonate or diethyl carbonate containing a lithium ion complex), or potassium hydroxide, sulfuric acid, or an organic carbonate (lithium ion complex (LiPF ₆ , A liquid mixture of non-coordinating anion salts such as LiAsF ₆ , LiClO ₄ , LiBF ₄ and LiCF ₃ SO ₃ ). When the electrolyte 6 is liquid, a polymer separator can be included in the electrolyte layer 6. In these embodiments, a separator is used. However, in general, when the electrolyte 6 is solid or gel, the electrolyte separator is unnecessary. When the electrode layer 5 is formed on both surfaces of the current collector 2, the electrolyte 6 is integrated on each surface of the current collector 2. And the structure produced in this way is passed through the calendar roll 7, and the electrode layer 5 is compressed to a predetermined thickness. If necessary, the electron beam irradiator 8 irradiates an electron beam through the electrolyte 6 to cure the binder.

  FIG. 2 is a diagram for explaining a method for manufacturing an electrode that does not include the electrolyte 6. By combining the technique shown in FIG. 2 with the technique shown in FIG. 1, an electrochemical cell 11 as shown in FIG. 3 can be produced. For example, the method shown in FIG. 1 can be used to construct the anode or cathode (current collector 2 and electrode layer 5) and electrolyte 6. The method shown in FIG. 2 can be used to construct a counter electrode that does not include electrolyte 6. And an electrochemical cell can be comprised by mutually superimposing and integrating the structure produced by the method of FIG. 1 and 2. FIG.

  For example, FIG. 3 schematically illustrates a lithium ion electrochemical cell 11 that can be made in accordance with the present invention. As illustrated, the cell 11 includes a current collector 2, and electrode layers 5 are laminated on both surfaces of the current collector 2. The electrode layer 5 includes an anode (−) or cathode (+) active material 10 and an actinic / electron beam curable polymer binder coating 9. In FIG. 3, for the sake of illustration, the electrode material 10 and the binder coating 9 are shown as different layers. An electrolyte 6 and optionally an electrolyte separator (not shown) can be laminated on each electrode layer 5. As will be apparent to those skilled in the art, a lithium ion battery may include any number of electrochemical cells 11 connected in series or in parallel as desired. Also, as will be apparent to those skilled in the art, in addition to the cell 11, the lithium ion battery configured in accordance with the present invention may further include an insulating material, a casing, a control circuit, a connector, and the like. Further, the lithium ion battery can be, for example, a cylindrical, square, pouch, or any other type of lithium ion battery known in the art.

  Moreover, EDLC can be comprised by integrating the 1st electrode and the 2nd electrode same as it with the suitable electrolyte and separator which were arrange | positioned among them. For example, referring to FIG. 4, EDLC 40 may include a first aluminum current collector 42 and a second aluminum current collector 43. The first current collector 42 and the second current collector 43 can be separated from each other by a separator 46. The first layer 44 and the second layer 45 formed on both sides of the separator 46 may be the same or different from each other. For example, both the first layer 44 and the second layer 45 can include a mixture of actinic / electron beam curable binder 50 and particulate material 52 (eg, graphite). Separator 46 can be any standard separator, such as a porous PTFE membrane.

The present invention can provide various advantages. For example, the method of the present invention can greatly reduce the manufacturing costs of electrodes and products containing the electrodes. The advantages of the present invention include, but are not limited to, the following (a) to (d).
(A) The processing time for curing the electrode binder can be greatly shortened.
(B) significantly reduce capital and operating costs by eliminating the need for thermal curing ovens and the associated energy inefficient thermal drying, and instead using actinic / electron curing stations. it can.
(C) The space, buildings, infrastructure and maintenance associated with thermosetting can be greatly reduced. For example, a conventional thermoset line is 100 ft long and the line speed is 10-20 ft / min. On the other hand, in the present invention, two UV lamps are placed 2 feet long (instead of a 100 foot production line) to produce a battery at 200 ft / min. In order for the speed of the thermoset line to be 200 feet / min, the thermoset section of the production line must be 1000 to 2000 ft long, ie the building length should be 0.2 to 0.4 miles. is there.
(D) Since the need for organic solvents can be greatly reduced or eliminated, the cost of procurement, recovery and disposal of volatile organic compounds (VOC) can be greatly reduced or eliminated.

  The invention can be better understood with reference to the following examples.

  Examples 1-4

  It has been demonstrated that a coating formed on an aluminum substrate by curing with actinic / electron beams can maintain bonding to the aluminum substrate under the simulated conditions of a lithium ion battery. Four samples were tested. The composition of each sample is shown in Table 1 below. The value of each composition is shown in wt%. For each sample, the binder coating composition was coated on 2 inch x 2 inch aluminum foil. Each sample was weighed after UV curing. The cured sample was placed in a container, immersed in a mixture of 40% by weight ethylene carbonate and 60% by weight dimethyl carbonate, and then placed in an oven. The oven was kept at about 60 ° C. (140 ° F.) for 2 weeks. Over the course of about 1 hour of the test, the oven temperature reached about 82 ° C. (180 ° F.). The oven temperature and atmosphere serve to simulate the temperature and electrolyte composition commonly found in operating lithium ion batteries. The test results are shown in Table 1 below.

¹ Reactive epoxy acrylate oligomer / monomer mixture from Sartomer Co. (Exton, PA)
² UV photoinitiator from Ciba Specialty Chemicals (Tarrytown, NY)
³ Reactive liquid rubber oligomer from Kuraray Co. Ltd. (Pasadena, TX)
⁴ Polyethylene glycol 200 diacrylate reactive diluent monomer from Sartomer Co. (Exton, PA)
⁵ Isobornyl acrylate reactive diluent monomer from Sartomer Co. (Exton, PA)
⁶ UV photoinitiator from Lamberti USA Inc. (Conshohocken, PA)
⁷ UV photoinitiator from Ciba Specialty Chemicals (Tarrytown, NY)
⁸ 8γ-glycidoxypropyltrimethoxysilane binder from Momentive Performance Materials (Albany, NY)

  As shown in Table 1, in samples 1 and 2 containing UC-102 (reactive liquid rubber oligomer), a coating that was firmly bonded to the aluminum substrate was formed. There was very little weight gain after samples 1 and 2 were soaked in the carbonate mixture for 2 weeks. On the other hand, Sample 3 containing a reactive epoxy acrylate oligomer / monomer mixture (a bisphenol epoxy acrylate oligomer diluted with 20% by weight hexanediol diacrylate) formed a coating peeled from the aluminum substrate. The weight increase of sample 3 was 21.7%. Similarly, Sample 4 composed of 95% by weight reactive diluent monomer and 5% by weight photoinitiator also formed a significantly exfoliated coating. The weight increase of sample 4 was 9.9%. From the above, it was found that Samples 1 and 2 are suitable mixtures as electrode binders. Samples 3 and 4 also demonstrated that common acrylate mixtures are not suitable for use as electrode binders.

  Example 5

200 g of a mixture consisting of 90% by weight of LiMn ₂ O ₄ , 6% by weight of carbon black and 4% by weight of a mixture of UC-102 (about 50% by weight) and isobornyl reactive diluent (50% by weight) was added to the laboratory. Mixed in a batch using a magnetically assisted impact coating apparatus (MAIC) of scale. As a result of this test conducted using a MAIC apparatus, a liquid mixture of UC-102 (reactive liquid rubber oligomer) and isobornyl acrylate was well dispersed as a coating on the surface of solid particles of LiMn ₂ O ₄ and carbon. I was able to.

  Example 6

In Example 5, LiMn ₂ O ₄ and carbon particles coated with a mixture of UC-102 and isobornyl acrylate were applied onto an aluminum foil substrate and dried. Thereafter, the coating material applied on the aluminum foil substrate was exposed to an electron beam (50 Mrad) and cured. After the electron beam (EB) curing, the aluminum foil substrate was rotated, and then the binding property of the material to the aluminum foil substrate was observed. There was substantially no such material remaining bonded to the aluminum foil substrate.

  Example 7

The coating material prepared by mixing LiMn ₂ O ₄ coated with a mixture of UC-102 and isobornyl acrylate in Example 5 and carbon particles with about 40% by volume of acetone was applied onto an aluminum foil substrate, and about 10%. A layer of mil (0.25 mm) was formed. When about 40% by volume of acetone was added as a wetting agent, the viscosity of the material decreased to a viscosity sufficient to coat the material on an aluminum foil substrate. The material was then air dried for a few seconds to evaporate the acetone. After fully evaporating the acetone, the material was cured by exposure to an electron beam (50 Mrad). After the electron beam (EB) curing, the aluminum foil substrate was rotated, and then the binding property of the material to the aluminum foil substrate was observed. The material remained well bonded to the aluminum foil substrate.

  Example 8

In Example 5, a coating material prepared by mixing LiMn ₂ O ₄ coated with a mixture of UC-102 and isobornyl acrylate and carbon particles with about 40% by volume of dimethyl carbonate electrolyte was applied on an aluminum foil substrate. An approximately 10 mil (0.25 mm) layer was formed. About 40% by volume dimethyl carbonate electrolyte as a wetting agent was added to enhance the bond between the material and the aluminum foil substrate. The material was then cured by exposure to electron beam (50 Mrad). The material was not completely dry before electron beam (EB) curing. After the electron beam (EB) curing, the aluminum foil substrate was rotated, and then the binding property of the mixture to the aluminum foil substrate was observed. The material remained well bonded to the aluminum foil substrate. From this result, it was demonstrated that the wetting agent electrolyte can enhance the bondability between the binder and the aluminum foil so as to bond well with the aluminum foil when the binder is cured. The wetting agent electrolyte does not bind to the aluminum foil and does not become part of the polymer.

  As shown in Examples 6-8, a small amount of wetting agent is required to enhance the bondability between the binder, particles and the aluminum foil substrate during actinic / electron beam polymerization. Example 8 shows that an electrolyte material commonly used in lithium ion batteries can be used as a wetting agent to enhance the wettability between the particles, binder and aluminum foil substrate. It is known that the hydrophilicity of some electrolyte materials requires humidity control in the manufacturing process.

  Example 9

A mixture comprising 90% by weight LiMn ₂ O ₄ and 4% by weight carbon particles coated with 6% by weight binder coating composition was prepared using a magnetically assisted collision coating technique. The binder coating composition comprises 47 wt% UC-102 (reactive liquid rubber oligomer), 47 wt% isobornyl acrylate, 4 wt% Esacure KIP 100F photoinitiator, 0.5 wt% % Irgacure 819 photoinitiator and 1.5 wt% Silquest A-187 binder. The cathode coating material was applied to an aluminum foil substrate of about 26 microns thickness that had been cleaned by immersion in a 5% acetic acid solution for 10 seconds, and a thickness of about 26 microns and 1 using a flat knife. Widened to inches wide. The coated aluminum foil was then compressed through a two roller jeweler's press to increase the contact between the aluminum foil, solid particles and binder. The structure was then exposed to actinic radiation (UV) by two passes under a 400 Watt / inch D bulb and Fusion 1250 irradiator driven by a Miltec MP-400 power supply. This process was repeated with the cathode coating material compression ratio in the jewelers press being about 10% to about 40%. After UV curing, the aluminum foil substrate was rotated, and then the binding properties of the cathode particles to the aluminum foil substrate were observed. In all cases, the cathode particles were not sufficiently bonded to the aluminum foil substrate, and the bonding rate was less than 5%. Further, the bonding between the cathode particles was insufficient, and the bonding rate was less than 10%.

  Example 10

90 wt% of LiMn ₂ O _4, a mixture containing the 4 wt% were mixed in the binder coating composition of 6 wt% and carbon particles were prepared by using the magnetic support collision coating techniques. The binder coating composition comprises 47% by weight UC-102, 47% by weight isobornyl acrylate, 4% by weight Esacure KIP 100F photoinitiator, and 0.5% by weight Irgacure 819 photoinitiator. And 1.5 wt% Silquest A-187 binder. The mixture was prepared by mixing the cathode coating material with about 15 wt% isopropyl alcohol as a wetting agent by simple stirring in a beaker. The mixture was applied onto an aluminum foil substrate and spread using a flat knife to a thickness of about 26 microns and a width of 1 inch. The aluminum foil was washed by dipping in a 5% acetic acid solution for 10 seconds. The coated aluminum foil was then exposed to actinic radiation (UV) by two passes under a 400 Watt / inch D bulb and Fusion 1250 irradiator driven by a Miltec MP-400 power supply. The belt speed was set at 20 feet / minute. This process was repeated with belt speeds set at 50 ft / min, 100 ft / min and 150 ft / min. After UV curing, the aluminum foil substrate was rotated, and then the binding property was observed. The bondability was good at 20 ft / min, 50 ft / min and 100 ft / min. At 150 feet / minute, the bondability was good in some areas, but not good in other areas. This indicates that the cure rate needs to be slower than 150 feet / minute.

  Example 11

A mixture containing 40 wt% carbon and 60 wt% binder was prepared using a standard 700 RPM stirrer. The binder coating composition comprises 47% by weight UC-102, 47% by weight isobornyl acrylate, 4% by weight Esacure KIP 100F photoinitiator, and 0.5% by weight Irgacure 819 photoinitiator. And 1.5 wt% Silquest A-187 binder. To this carbon binder mixture, LiCoO ₂ and isopropyl alcohol as a wetting agent are mixed while gradually increasing the amount of LiCoO ₂ , and 7.5 wt% carbon binder mixture, 25 wt% isopropyl alcohol and A final mixture consisting of 67.5 wt% LiCoO ₂ was prepared. The mixture was coated on a cleaned aluminum foil substrate by dipping in a 5% acetic acid solution for 10 seconds and spread to a thickness of about 26 microns and a width of 1 inch using a flat knife. The coated aluminum foil was then exposed to actinic radiation (UV) using two 400 Watt / inch D bulbs and a Fusion 1250 irradiator driven by a Miltec MP-400 power supply. The belt speed was set at 50 feet / minute. The bonding property between the particles and the bonding property of the particles to the aluminum foil substrate were good. The isopropyl alcohol wetting agent was completely evaporated by brief exposure to the UV lamp chamber. The belt speed was set at 100 feet / minute, 150 feet / minute, and 200 feet / minute. The coated aluminum foil was folded or unfolded to test the binding properties of the coating. Bonding was good at all three cure rates. From this, a UV curable type containing a wetting agent to facilitate deposition and to speed up the coating curing process rate to 200 feet / min (ie, less than 1 second exposure to a UV lamp) It has been demonstrated that sufficient binding of carbon and common active lithium cathode materials to current collectors can be achieved by using a binder mixture.

  Example 12

A mixture containing 40 wt% carbon and 60 wt% binder was prepared using a standard 700 RPM stirrer. The binder comprises 47 wt.% CN301, 23.5 wt.% Isobornyl acrylate, 23.5 wt.% SR-238 HDODA, 4.5 wt.% SM303 photoinitiator, and 1. 5% by weight Genorad 51 dispersant. To this carbon binder mixture, LiCoO ₂ and isopropyl alcohol as a wetting agent are mixed while gradually increasing the amount of LiCoO ₂ , and 7.5 wt% carbon binder mixture, 25 wt% isopropyl alcohol and A final mixture consisting of 67.5 wt% LiCoO ₂ was prepared. The mixture was coated on a cleaned aluminum foil substrate by dipping in a 5% acetic acid solution for 10 seconds and spread to a thickness of about 26 microns and a width of 1 inch using a flat knife. The coated aluminum foil was then exposed to actinic radiation (UV) using two 400 Watt / inch D bulbs and a Fusion 1250 irradiator driven by a Miltec MP-400 power supply. The belt speed was set at 50 feet / minute. The bonding property between the particles and the bonding property of the particles to the aluminum foil substrate were good. The coating speed was tested by setting the belt speed to 100 ft / min, 150 ft / min, 200 ft / min and folding or spreading the coated aluminum foil. In all, the binding was good.

  Example 13

A mixture containing 40 wt% carbon and 60 wt% binder was prepared using a standard 700 RPM stirrer. The binder includes 47 wt% CN301, 47 wt% isobornyl acrylate, 4 wt% Esacure KIP 100F photoinitiator, 0.5 wt% Irgacure 819 photoinitiator, 1.5 wt% % By weight of Silquest A-187 binder. To this carbon binder mixture, LiCoO ₂ and isopropyl alcohol as a wetting agent are mixed while gradually increasing the amount of LiCoO ₂ , and 7.5 wt% carbon binder mixture, 25 wt% isopropyl alcohol and A final mixture consisting of 67.5 wt% LiCoO ₂ was prepared. The mixture was coated on a cleaned aluminum foil substrate by dipping in a 5% acetic acid solution for 10 seconds and spread to a thickness of about 26 microns and a width of 1 inch using a flat knife. The coated aluminum foil was then exposed to actinic radiation (UV) using two 400 Watt / inch D bulbs and a Fusion 1250 irradiator driven by a Miltec MP-400 power supply. The coating speed was tested by setting the belt speed to 200 feet / minute and folding or spreading the coated aluminum. The bondability was good. The coated aluminum coupon was then immersed in a 60% / 40% dimethyl / ethylene carbonate mixture and left at about 60 ° C. (140 ° F.) for 2 weeks. The increase in weight after the test period of 2 weeks was substantially zero, and the bondability to the aluminum and the bondability between the particles were good. Thus, a cathode coating formed by applying a UV curable binder mixture and curing at a process rate of 200 ft / min, i.e. with a UV light exposure time of less than 1 second, is the electrolyte of a lithium ion battery. It has been demonstrated that binding and physical integrity are maintained even after two weeks of exposure to the environment.

  Example 14

A mixture containing 40 wt% carbon and 60 wt% binder was prepared using a standard 700 RPM stirrer. The binder comprises 47 wt% CN301, 23.5 wt% isobornyl acrylate, 23.5 wt% CD563 AHDODA, 4.5 wt% SM303 photoinitiator, 1.5 wt% % Of Genorad 51 dispersant. To this carbon binder mixture, LiCoO ₂ and isopropyl alcohol as a wetting agent are mixed while gradually increasing the amount of LiCoO ₂ , and 7.5 wt% carbon binder mixture, 25 wt% isopropyl alcohol and A final mixture consisting of 67.5 wt% LiCoO ₂ was prepared. The mixture was coated on a cleaned aluminum foil substrate by dipping in a 5% acetic acid solution for 10 seconds and spread to a thickness of about 26 microns and a width of 1 inch using a flat knife. The coated aluminum foil was then exposed to actinic radiation (UV) using two 400 Watt / inch D bulbs and a Fusion 1250 irradiator driven by a Miltec MP-400 power supply. The coating was tested for bondability by setting the belt speed to 200 feet / minute and folding or spreading the coated aluminum. The bondability was good. The coated aluminum coupon was then immersed in a 60% / 40% dimethyl / ethylene carbonate mixture and left at about 60 ° C. (140 ° F.) for 2 weeks. The increase in weight after the test period of 2 weeks was substantially zero, and the bondability to the aluminum and the bondability between the particles were good.

  Examples 15-17

Lithium ions that can be fully charged and discharged through multiple cycles and can exhibit general performance in lithium ion battery cathodes using common electrode active compounds such as LiCoO ₂ and LiMn ₂ O ₄ It has been demonstrated that battery cathodes can be made using UV curable binders. Three samples were tested. The cathode current collector coating composition is shown in Table 2 below. Each sample is an approximately 2 inch x 6 inch, 26 micron thick aluminum sheet coated with a combination of binder mixture, carbon, lithium compound, and isopropyl alcohol as a wetting agent. First, the binder mixture and carbon were mixed together using a D-10 mixer available from H. Duke Enterprises, Pleasant View, Tennessee. Further mixing was achieved using an EXAKT Model 80S Three Roll Mill available from EXAKT Technologies, Oklahoma City, Oklahoma, so that a uniform mixture was obtained. The binder mixture, carbon, lithium compound, and isopropyl alcohol as a wetting agent were mixed with each other in the ratio shown in the “Coating” column of Table 2 below. The above components were mixed using the D-10 mixer described above. The coating mixture thus prepared was applied to an aluminum sheet current collector using a micrometer-adjusted knife edge applicator set to a thickness of 75 microns. Samples of the coated current collector were cured at various speeds shown in Table 2 under a 2,600 watt / inch, 10 inch long D-type UV lamp. As a result of the UV curing process, only the carbon binder mixture and the lithium compound remained on the current collector in the proportions shown in the “cured coating” column of Table 2 below. All three samples that passed through the UV curing lamp showed good binding of the carbon and lithium compound particles to the current collector or between the particles. All three samples were calendered with a 75 micron thick or 50 micron thick roll press. The samples were sent to the US Department of Energy Argonne National Laboratory for electrochemical testing.

At Argonne National Laboratory, a circular coupon with the same diameter as that of the 2032 coin cell was cut from each sample. Using lithium metal as the anode, Celgard 2325 (PP / PE / PP trilayer membrane available from Celgard LCC, Charlotte, NC) as the separator, ethylene carbonate: ethylene methyl carbonate (weight A 2032 coin-shaped half-cell was made from a UV cured cathode using 1.2 moles of LiPF ₆ included in the ratio 3: 7) as the electrolyte. After the half cell was assembled in a helium filled glove box, an electrochemical charge / discharge test was performed using a Maccor 4400 electrochemical test apparatus.

¹ Photoinitiator manufactured by Chitec Technology Corp. (Taipei, Taiwan)
² Photosensitizer manufactured by Chitec Technology Corp. (Taipei, Taiwan)
³ UV photoinitiator from Ciba Specialty Chemicals (Tarrytown, NY)
⁴ Isobornyl acrylate reactive diluent monomer from Sartomer Co. (Exton, PA)
⁵ Hexanediol acrylate reactive diluent monomer from Sartomer Co. (Exton, PA)
⁶ Polybutadiene dimethyl dimethyl acrylate oligomer from Sartomer Co. (Exton, PA)
⁷ Dispersant from Rahn USA Corp. (Aurora, IL)
⁸ Photoinitiator from Chitec Technology Corp. (Taipei, Taiwan)
⁹ Alkoxylated hexanediol diacrylate reactive diluent monomer from Sartomer Co. (Exton, PA)
¹⁰ Carbon powder manufactured by Sigma-Aldrich Co (St. Louis, MO)
¹¹ Lithium cobalt oxide from Sigma-Aldrich Co (St. Louis, MO)
¹² Lithium magnesium oxide manufactured by Sigma-Aldrich Co (St. Louis, MO)
¹³ Photoinitiator from Chitec Technology Corp. (Taipei, Taiwan)
¹⁴ Graphite from Timcal Graphite and Carbon (Westlake, Ohio)
¹⁵ N-methyl-2-pyrrolidone from Worldchem LTD, (Hafei, Anhui, China)

  The results of the initial charge and discharge electrochemical tests of Examples 15, 16 and 17 are shown in FIGS. 5, 6 and 7, respectively. Sample 1 corresponds to Example 15 (FIG. 5), Sample 2 corresponds to Example 16 (FIG. 6), and Sample 3 corresponds to Example 17 (FIG. 7). For Sample 1 (Example 15), the charge and discharge cycles were repeated. Sample 1 was charged and discharged at a C / 5 rate of 24 milliamps / gram. The charge capacity of Sample 1 after 10 cycles was 61% of the initial charge capacity.

The composition of Example 15 contains about 7.4 mg / cm ² of the active substance LiCoO ₂ / LiMn ₂ O ₄ . The current density was C / 5, 24 mA / g, and the cut-off voltage was 3.0 to 4.3V. The charge capacity was 130 mAh / g and the discharge capacity was 105 mAh / g.

The composition of Example 16 contains about 5.2 mg / cm ² of the active substance LiCoO ₂ / LiMn ₂ O ₄ . The current density was C / 5, 24 mA / g, and the cut-off voltage was 3.0 to 4.3V. The charge capacity was 101 mAh / g and the discharge capacity was 61 mAh / g.

The composition of Example 17 contains about 5.2 mg / cm ² of the active substance LiMn ₂ O ₄ . The current density was C / 5, 24 mA / g, and the cut-off voltage was 3.0 to 4.3V. The charge capacity was 107 mAh / g and the discharge capacity was 54 mAh / g.

  Example 18

  By using the UV curable binder of the present invention, a lithium ion battery anode coating can be formed on the current collector that can maintain integrity and binding properties in the presence of a typical lithium ion battery electrolyte. We have demonstrated that we can do it. The UV curable binder mixture of the present invention was prepared using conventional mixing techniques at the ratios shown in Examples 18-19 of “Binder and Carbon Mixtures” in Table 2. Using conventional mixing techniques, an anode coating mixture was prepared by adding graphite to the UV curable binder in the proportions shown in Examples 18-19 of “Coating” in Table 2. The coating mixture thus prepared is applied to a copper foil current collector using a micrometer-adjusted knife edge applicator set to a thickness of 75 microns and then driven by a Miltec MP-400 power supply. Two 400 Watt / inch D bulbs and Fusion 1250 irradiators were used to expose to actinic radiation at a rate of 200 feet / minute. Isopropyl alcohol evaporated during exposure to UV radiation. The cured coating was calendered to a thickness of 50 microns. After curing and calendering, the coated current collector 2 inch x 2 inch coupon is dipped in a 60% / 40% dimethyl / ethylene carbonate mixed solution at about 60 ° C (140 ° F). Left for a week. The increase in weight after the test period of 1 week was substantially zero, and the bondability to copper and the bondability between the particles were good.

  Example 19

  By using the UV curable binder of the present invention, an electric double layer capacitor (EDLC) electrode coating that can maintain integrity and adhesion in the presence of a typical EDLC electrolyte is formed on the current collector Prove that you can. The UV curable binders of the present invention were prepared using conventional mixing techniques at the ratios shown in the Examples 18-19 column of “Binder and Carbon Mixtures” in Table 2. Using conventional mixing techniques, an electrode coating mixture was prepared by adding graphite to the UV curable binder in the ratios shown in Examples 18-19 of Table 2 under "Coating". The coating mixture thus prepared was applied to a copper foil current collector using a micrometer-adjusted knife-edge applicator set to a thickness of 75 microns and then driven by a Miltec MP-400 power supply. Were exposed to actinic radiation at a rate of 200 feet / minute using two 400 watt / inch D bulbs and a Fusion 1250 irradiator. Isopropyl alcohol evaporated during exposure to UV radiation. The cured coating was calendered to a thickness of 50 microns. After curing and calendering, the coated current collector 2 inch x 2 inch coupon is dipped in a 60% / 40% dimethyl / ethylene carbonate mixed solution and heated at about 60 ° C (140 ° F). Left for a week. The increase in weight after the test period of 1 week was substantially zero, and the bondability to aluminum and the bondability between the particles were good.

  While the above description allows those skilled in the art to implement what is currently considered to be the best mode, there are various variations, combinations and equivalents of the above-described embodiments, methods and examples. Will be understood by those skilled in the art. Accordingly, the present invention is not limited to the embodiments, methods, and examples described above, but is intended to encompass all embodiments and methods that fall within the scope of the appended claims.

Claims (18)

An electrode,
A current collector and a polymer layer bonded to the surface of the current collector;
The polymer layer comprises a cross-linked matrix formed from a functionalized rubber polymer and a conductive particulate material;
An electrode, wherein the cross-linked matrix comprises an actinic / electron beam reaction curable cross-linking agent covalently bonded to the functionalized rubber polymer. The electrode according to claim 1,
The electrode, wherein the functionalized rubber polymer includes at least one of monomer units of isoprene, butadiene, cyclopentadiene, ethylidene norbornene, or vinyl norbornene, or a combination thereof. The electrode according to claim 1 or 2, wherein
An electrode, wherein the cross-linking agent is covalently bonded to the functionalized rubber polymer via a carboxy, acrylic, vinyl, vinyl ether or epoxy-reactive functional group of the rubber polymer. An electrode according to any one of claims 1 to 3,
An electrode, wherein the functionalized rubber polymer is a (meth) acrylated rubber polymer having a backbone represented by any one of the following chemical formulas.
(A)

However, m is about 100 to about 1500, and n is 1 to about 20.
(B)

Where m is from about 10 to about 1000 and n is from 1 to about 20.
(C)

However, n is about 5 to about 2000. The electrode according to any one of claims 1 to 4, wherein
The electrode, wherein the particulate material contains carbon such as graphene, activated carbon, graphite, low sulfur graphite, carbon nanotube, or a combination thereof. An electrode according to any one of claims 1 to 5,
The electrode, wherein the particulate material contains a metal oxide salt or a lithium compound. The electrode according to any one of claims 1 to 6,
Adjacent to the electrode, an additional layer such as a second electrode or separator is provided,
One or more of the additional layers optionally comprising an electrolyte. The electrode according to any one of claims 1 to 7,
The electrode wherein the polymer layer has a thickness of about 1 micron to about 500 microns.   A battery, such as a lithium ion battery, comprising the electrode according to any one of claims 1 to 8.   An electric double layer capacitor comprising the electrode according to any one of claims 1 to 8. A method for producing an electrode, comprising:
A binder coating composition comprising a functionalized rubber polymer and a crosslinker capable of forming a covalent bond when exposed to actinic or electron radiation and having a melt viscosity of less than about 20 Pascal seconds or less than about 10 Pascal seconds Mixing the material with the electrode particulate material to prepare a mixture;
Applying the mixture to a surface of a current collector to form a mixture layer;
Exposing the mixture layer to actinic or electron beams, thereby cross-linking the functionalized rubber polymer. The method of claim 11, comprising:
The method wherein the binder coating composition contains the functionalized rubber polymer in an amount of about 20% to 100% by weight of the composition. 13. A method according to claim 11 or claim 12, comprising:
The method wherein the binder coating composition further comprises one or more of a reactive diluent, a wetting agent and a photoinitiator. A method according to any one of claims 11 to 13, comprising
A method wherein the cross-linking agent is a reactive diluent. 15. A method according to any one of claims 11 to 14, comprising
The electrode particulate material comprises carbon, metal oxide or lithium compound. A method according to any one of claims 11 to 15, comprising
The method further comprising grinding the functionalized rubber polymer and the electrode particulate material. A method according to any one of claims 11 to 16, comprising
The method further includes the step of stacking a second electrode on the electrode. A method according to any one of claims 11 to 17, comprising
The method further comprising disposing a separator between the first electrode and the second electrode.

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